FLOYD COUNTY, IN (WAVE) – A teenager accused of firing a flare gun into a New Albany home in January, causing a fire that killed three young siblings and injured a fourth, has been offered a plea deal.

Floyd County Prosecutor Keith Henderson said 18-year-old Cody Cashion has until August 5 to accept the deal or go to trial. Cashion is charged with three counts of felony murder and one count of arson.

In what was supposed to be the final pretrial hearing for Cashion on Tuesday, the defense was granted a continuance, pushing the trial from July to September 2 and allowing for two more pretrial conference dates to make sure everything is set for trial.

If Cashion accepts the plea deal, he will avoid trial and a date will be set for his sentencing.

"It's a reasonable offer for the severity of what's been charged," said Floyd County Prosecutor Keith Henderson.

Marie Clark, the victims' grandmother, said she wavers back and forth on what would be best -- a plea deal or trial. She said she just wants justice for her grandchildren.

"They were beautiful babies, and they just didn't deserve this," said Clark, "innocent babies caught in something that had nothing to do with them, and it just hurts to see the person that's responsible," Clark said. " It just hurts."

Shelby Makowsky, 18, accepted a plea deal in the case on April 22. She changed her plea from not guilty to guilty on a charge of conspiracy to commit arson. She faces between six and 20 years in prison and a possible $10,000 fine when she is sentence on May 29.

Makowsky admitted that she was with Cashion, 19-year-old Kylie Jenks and a 17-year-old girl on January 4 when Cashion started the fire that killed 2-year-old Trinity, 4-year-old Tyrese and 6-year-old Tai'zah Hughes and badly burned their sister, 5-year-old Tatyana Hughes. Prosecutors said the group was trying to exact revenge on a man who lived at the home. Makowsky told prosecutors Johnathan "Udy" Stewart had failed to pay them for stolen electronics they sold him in an effort to raise bail money for Cashion who had been jailed in December on a theft charge.

Jenks and the juvenile girl also are charged with conspiracy to commit murder.